1 files changed, 101 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/testing/isolation.rb b/activesupport/lib/active_support/testing/isolation.rb
new file mode 100644
index 0000000000..68bda35980
--- /dev/null
+++ b/activesupport/lib/active_support/testing/isolation.rb
@@ -0,0 +1,101 @@
+require 'rbconfig'
+
+module ActiveSupport
+  module Testing
+    module Isolation
+      require 'thread'
+
+      def self.included(klass) #:nodoc:
+        klass.class_eval do
+          parallelize_me!
+        end
+      end
+
+      def self.forking_env?
+        !ENV["NO_FORK"] && ((RbConfig::CONFIG['host_os'] !~ /mswin|mingw/) && (RUBY_PLATFORM !~ /java/))
+      end
+
+      @@class_setup_mutex = Mutex.new
+
+      def _run_class_setup      # class setup method should only happen in parent
+        @@class_setup_mutex.synchronize do
+          unless defined?(@@ran_class_setup) || ENV['ISOLATION_TEST']
+            self.class.setup if self.class.respond_to?(:setup)
+            @@ran_class_setup = true
+          end
+        end
+      end
+
+      def run
+        serialized = run_in_isolation do
+          super
+        end
+
+        Marshal.load(serialized)
+      end
+
+      module Forking
+        def run_in_isolation(&blk)
+          read, write = IO.pipe
+          read.binmode
+          write.binmode
+
+          pid = fork do
+            read.close
+            yield
+            write.puts [Marshal.dump(self.dup)].pack("m")
+            exit!
+          end
+
+          write.close
+          result = read.read
+          Process.wait2(pid)
+          return result.unpack("m")[0]
+        end
+      end
+
+      module Subprocess
+        ORIG_ARGV = ARGV.dup unless defined?(ORIG_ARGV)
+
+        # Crazy H4X to get this working in windows / jruby with
+        # no forking.
+        def run_in_isolation(&blk)
+          require "tempfile"
+
+          if ENV["ISOLATION_TEST"]
+            yield
+            File.open(ENV["ISOLATION_OUTPUT"], "w") do |file|
+              file.puts [Marshal.dump(self.dup)].pack("m")
+            end
+            exit!
+          else
+            Tempfile.open("isolation") do |tmpfile|
+              env = {
+                ISOLATION_TEST: self.class.name,
+                ISOLATION_OUTPUT: tmpfile.path
+              }
+
+              load_paths = $-I.map {|p| "-I\"#{File.expand_path(p)}\"" }.join(" ")
+              orig_args = ORIG_ARGV.join(" ")
+              test_opts = "-n#{self.class.name}##{self.name}"
+              command = "#{Gem.ruby} #{load_paths} #{$0} #{orig_args} #{test_opts}"
+
+              # IO.popen lets us pass env in a cross-platform way
+              child = IO.popen([env, command])
+
+              begin
+                Process.wait(child.pid)
+              rescue Errno::ECHILD # The child process may exit before we wait
+                nil
+              end
+
+              return tmpfile.read.unpack("m")[0]
+            end
+          end
+        end
+      end
+
+      include forking_env? ? Forking : Subprocess
+    end
+  end
+end